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Capers Jones, of Software Productivity Research, is an acknowledged expert on all things metric in the computer field. His
previous report on the magnitude of y2k is considered a standard work.
In this essay, he points out that y2k is one of many date disruptions that will take place as a result of originally limited memory space. It's cheap now; it wasn't then; and that will make all the difference.
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Version 4 – April 23, 1998
Abstract
The year 2000 date problem is not the only calendar problem causing trouble for software applications. This report highlights some of the known date problems that are likely to affect software applications over the next 50 years. Other date problems that might impact software include the date at which global positioning satellites (GPS) roll over, the dates at which commodities switch to the Euro, the dates at which the UNIX and C libraries roll over, and some hazardous date patterns which have been used for non-date purposes in software applications. In addition, at some point early in the next century the numbers of digits assigned to social security numbers and telephones will run out of capacity.
Over the next 50 years at least 100,000,000 software applications globally will need modification because of various date problems. The total costs of these modifications can top $5 trillion dollars. The report concludes that because date problems with computers and software are so widespread, serious, and expensive, a new international standard for dates should be developed for computer purposes. The proposed date format includes a "key" field which is used to identify which specific date format follows. This method would allow older date formats to be used, and would support multiple calendars. . . .
Two common methods of recording dates are used in computers and software applications: 1) Storing dates using conventional date representation formats such as the year, month, and day; 2) Accumulating the number of seconds from an arbitrary starting point. Both of these methods have been troubled by insufficient storage space.
For conventional date formats the most traditional way to conserve space was to truncate four-digit years fields and use only two digits so that a year such as 1998 would be stored as 98.
For the method of keeping track of dates by accumulating seconds from an arbitrary starting point the size of the field is usually limited to no more than 4 bytes of storage space. This method will "overflow" and reset to zero or to the initial starting point when capacity is exceeded.
For example, the date "buckets" used on global positioning satellites (GPS) record time for 1023 weeks, and then reset to week 0 on the 1024th week and continue this cycle about every 20 years.
Starting in August of 1999 and continuing at intervals over the next 50 years both methods used by computers and software for dealing with dates will experience problems because of the historical practice of attempting to conserve storage space.
Both of these methods have worked reasonably well up until now, but both will run into serious problems when their storage boundaries are exceeded. What happens when the computer date storage volumes are exceeded is now a very serious issue that can cause untold economic damage and perhaps physical damages too, in the sense of shutting down electric power plants, stopping assembly lines, or grounding aircraft. Let us examine some of the known date problems that are going to affect computers and software over the next 50-year period. . . .
The cumulative costs of expanding numeric fields as their capacity is exceeded will erode many of the economic advantages of the use of computers and software. It is obvious that a more permanent general schema must be developed before the maintenance expenses trigger bankruptcy and litigation for hundreds of corporations and even for some governments.
None of these massive software updates will add useful new features or functions to applications. Their main purpose is merely to allow the applications to continue to operate when dates or information volumes exceed the available sizes of the fields originally set aside to store the information.
It is a shocking to consider that many of the economic advantages of the most powerful tools ever created by the human species for holding information will be lost due something as trivial as not setting aside enough room to hold dates or numeric information.
Nonetheless the future of computing and software over the next 50-year period will be severely disrupted by a series of massive maintenance updates due to inadequate field sizes for dates and numeric information. One by one, current date representation methods will fail, and other numeric data will encounter field size problems as well. . . .
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